Locking mechanism for a clockwork movement of a mechanical time fuse for a projectile



Aprnl 10, 1956 G. HOENGER 2,741,385

LOCKING M ANISM FOR A CLOCKWORK MOVEMENT OF A MECH CAL TIME FUSE FOR A PROJECTILE Filed April 23, 1951 [Ill Iwvewfar B @uLcZo h oe-ng LOCKING MECHANISM'FOR A CLOCKWORK MOVEMENT OF A MECHANICAL TIIVIE FUSE FOR A PROJECTILE Guido Hoenger, Zuchwil, Switzerland, assignor to Melina S. A., Binningen, Switzerland, a corporation of Switzerland Application April 23, 1951, Serial No. 222,344

Claims priority, application Switzerland July 10, 1950 3 Claims. (Cl. 102-84) This invention relates in general to projectile time fuses of the clockwork actuated type, and more particularly has reference to a safety mechanism for locking the clockwork against movement and releasable under the action of centrifugal force produced by rotation of the projectile in flight.

The known mechanisms for locking the clockwork movement in mechanical time fuses, lock the movement in inactive position and release it only at the time of firing, by unlocking it under the action either of the centrifugal force, or of inertia, but such locking mechanisms do not give suificient security against premature starting of the clockwork movement when the fuse is subjected to shock or vibration in the course of handling or transportation.

The principal object of the present invention is to provide mechanism for locking the clockwork movement in mechanical time fuses which will avoid the above pointed out disadvantage of the prior devices.

Another object of this invention is to provide a mechanism comprising at least two centrifugal clockwork movement locking members arranged symmetrically on either side of the axis of the fuse and cooperating one with the other, said members remaining constantly in mutual engagement, and each pivoting eccentrically and being subjected to the action of a spring tending to maintain the member in locking position, neither of said members being capable of moving out of its locking position, unless the other also does so.

The accompanying drawing shows, by way of example, one embodiment of the invention.

In the drawing:

Figure 1 is an elevation of the time fuse mechanism with locking device;

Figure 2 is a sectional view taken on line 2--2 of Fig. 1.

According to the present invention, the time fuse actuating clockwork locking mechanism comprises two centrifugally released locking levers 1 and 1a of general semi-annular shape, said levers being pivoted eccentrically at 2 and 2a respectively, near their ends, and carrying stop pins 3, 3a each located remotely from the pivoting axis 2, 2a. The levers 1 and 1a are mounted on the upper frame plate 11 of the clockworkmovement and the pins 3, 3a traverse this plate through openings 12 and 12a of arcuate shape, the center of curvature of which coincides with the pivots 2, 2a. The pins 3, 3a engage notches 8, 8a of the balance wheel 7 of the clockwork, which is locked in position of rest when the locking levers 1 and 1a are urged towards the axis of the fuse by two restoring springs 6, 6a respectively. The locking levers 1 and 1a each has a front nose 4, 4a provided on the ends of their long arms, and a rear nose 5, 5a provided on the ends of their short arms. The rear nose of one lever cooperates with the front nose of the other lever to maintain it in locking position. As seen in the drawing, the noses 5, 5a lie in contact with the noses 4a and 4 by the action of the springs 6 and 6a, in such a man- 2,741,185 Patented Apr. 10, 1956 'ice ner that neither of the levers can move out of its locking position unless the other lever is moved out of its lockmg position.

1' The operation of this locking mechanism is as folows:

In position of rest the balance wheel 7 is locked by the stop pins 3, 3a of the levers 1, 1a. To release the balance wheel 7, the stop pins 3, 3a must move out of the notches 8, 8a to occupy the positions indicated at 3 and 3". To allow the stop pins 3, 3a to occupy the positions 3 3" respectively, the locking levers 1, 1a must overcome the force of their restoring springs 6, 6a.

Assuming that a force in the same direction is applied to the locking levers 1 and In, such as might be caused by a shock or fall, as indicated at 13 and 13a in Fig. 2, the locking lever 1a urged by the force 13a will tend to move still further towards the center. The total force which will hold it against the center will be the sum of the force 13a and of the force of the restoring spring 6a. The locking lever 1 urged by the force 13 will tend to move outwardly to unlocking position. The total force urging it to move away from the center will be the difierence between the force 13 and the force of the restoring spring 6. In the present example, the locking lever 1a will be subjected to the total force greater than that acting on the locking lever 1. The latter will not be able to open since it is held by its nose 5 bearing against the nose 4a of the locking lever 1a. It is clear that regardless of the magnitude of the equal forces applied in the same direction to the locking mechanism, the latter will always remain locked, neither of the stop pins 3 or 3a being able to move out of the notch 8 or 8a of the balance wheel 7 under the action of such forces.

It is only opposed forces directed from the center outwardly that can cause the locking levers 1 and 1a to shift. Such forces, that isto say, centrifugal forces, are created only by a rotation of the mechanism about its axis. Now a fuse is not caused to rotate rapidly about its axis except upon firing and during flight of the projectile equipped with the fuse.

The locking levers 1, 1a will then open and the stop pins 3, 3a will abut against the ends of the openings 12, 12a of the frame plate 11, thus releasing the balance wheel 7 which is no longer arrested. The stop pins then occupy the positions 3, 3". The noses of the locking levers 1 and 1a will then occupy the positions shown in broken lines.

The locking mechanism described thus can operate only under centrifugal force. It is perfectly insensitive to shocks of any other nature, either feeble or violent, such as might result from vibration, falls, or any other causes. One locking lever cannot open unless the other also does so. One stop pin can never lie in locking position while the other stop pin is in release position. The twin locking levers are always simultaneously closed or simultaneously open.

It is clear that the mechanism may comprise more than two centrifugally released locking levers cooperating one with the other, and that instead of acting against the balance wheel of the clockwork movement, the locking members may act upon any other part of this movement capable of preventing premature starting of the clockwork.

Having described my invention, I claim:

1. A locking mechanism for a clockwork movement of a mechanical time fuse for a projectile adapted to rotate about its axis during flight, comprising at least two clockwork locking levers of general semi-annular form symmetrically and concentrically disposed on opposite sides of said axis, means symmetrically disposed on opposite sides of said axis for pivotally mounting said levers adjacent one of their ends for pivotal movement about axes parallel to said projectile axis, and proiding each lever with a long arm movable outwardly rider the action of centrifugal force upon rotation of he projectile about its axis, said levers being of a length nch that the long arm of each underlies the short arm If the other lever for preventing inward movement of he short arm and outward unlocking movement of the ong arm of each lever while the long arm of, the other ever is in its inner locking position, and spring means :ooperating with each lever to urge the long arm of each ever to its inner locking position; each end of the locking evers being tapered or nose-shaped, with the nose of the :nort arm of one lever interfitting with the nose of the ong arm of the other lever, said levers, when in locking aosition, having their inner and outer surfaces forming 'vubstantially annular rings, whereby a movement of only one of the levers will cause a corresponding movement at the other lever.

2. A locking mechanism for a clockwork movement of a mechanical time fuse for a projectile adapted to rotate about its axis during flight, comprising a frame plate of the clockwork movement extending transversely of said axis, at least two clockwork locking levers of general semi-annular form symmetrically and concentrically disposed on opposite sides of said axis, means carried by said plate and symmetrically disposed on opposite sides of said axis for pivotally mounting said levers eccentrically with respect to their centers of gravity for pivotal movement about axes parallel to said projectile axis outwardly under the action of centrifugal force upon rotation of the projectile about its axis, spring means urging said levers inwardly into locking position, and cooperating interlocking parts on the ends of said levers for preventing outward movement of either lever from locking position unless there is a corresponding outward movement of the other lever from locking position, said plate having openings therein and a pin carried by one end of each lever and extending through an opening in the plate to engage a part of the clockwork movement and lock the same when the levers are in their inner locking positions; said interlocking parts having contacting cam surfaces whereby a movement of only one of the levers will cause a corresponding movement of the other lever.

3. A locking mechanism for a clockwork movement of a mechanical time fuse for a projectile adapted to rotate about its axis during flight, comprising a frame plate of the clockwork movement extending transversely of said axis, at least two clockwork locking levers of general semi-annular form symmetrically and concentrically disposed on opposite sides of said axis, means carried by said piate and symmetrically disposed on opposite sides of said axis for pivotally mounting said levers eccentrically with respect to their centers of gravity for pivotal movement about axes parallel to said projectile axis outwardly under the'action of centrifugal force upon rotation of the projectile about its axis, spring means urging said levers inwardly into locking position, and cooperating interlocking parts on the ends of said levers for preventing outward movement of either lever from locking position unless there is a corresponding outward movement of the other lever from locking position, said plate having two arcuate openings therein, the centers of curvature of which coincide with said pivotal mounting means and a pin-carried by each lever and extending through an arcuate opening in the plate to engage a part of the clockwork movement and lock the same when the levers are in their inner locking positions; said interlocking parts having contacting cam surfaces whereby a movement of only one of the levers will cause a corresponding movement of the other lever.

References Cited in the file of this patent UNITED STATES PATENTS 988,610 Wieser Apr. 4, 1911 2,097,836 Junghans Nov. 2, 1937 2,130,720 Junghans Sept. 20, 1938 FOREIGN PATENTS 598,266 Great Britain Feb. 13, 1948 

